HOUSTON (AP) - Astronauts vowed to double-check, even triple-check, to make sure a bag of tools is properly tied down during a spacewalk Thursday so it doesn't float away like one did earlier this week.

"We're definitely not going to do it again. You're not going to see us lose another bag," lead spacewalker Heidemarie Stefanyshyn-Piper said in an interview from the international space station with The Associated Press.

During the two-week mission's first spacewalk Tuesday, the tool tote floated out of a larger bag as Stefanyshyn-Piper cleaned grease from a leaking grease gun. Tethered to the lost briefcase-sized bag were a pair of grease guns used to lubricate a jammed joint that controls the space station's rotating solar wing. The bag was one of the largest items ever lost by a spacewalking astronaut, and NASA guessed it cost about $100,000.

The mishap left Stefanyshyn-Piper and her fellow spacewalkers, Stephen Bowen and Robert "Shane" Kimbrough, with only a single pair of grease guns for three more spacewalks.

(AP) In this image provided by NASA the Space Shuttle Endeavour and the International Space Station...Full Image"We're going to double- and triple-check everything from here on out," Stefanyshyn-Piper said.